Human papillomavirus (HPV) infects epithelial cells and cause a variety of lesions ranging from common warts/verrucas to cervical neoplasia and cancer. These HPVs fall into “high-risk HPV types” and “low-risk HPV types” depending on the frequency with which they are found in cancers. Cervical cancer is diagnosed in nearly half a million women each year worldwide. It accounts for the second most deaths of all cancers in women. Persistent high-risk HPV infections are now recognized as the cause of essentially all cervical cancers. Therefore, it is very useful to stop the development of high grade cervical neoplasia by early detection and treatment of HPV infections.
Traditionally, genital HPV infection has been detected as abnormal cell changes on a Pap smear, a test used primarily to detect cancer of the cervix or conditions that may lead to cancer. During a Pap smear, the appearance of cervical cells is evaluated under a microscope. Certain changes in the cells may indicate an HPV infection, but there is no clear distinction between high- and low-risk types.
DNA testing for HPV can be used as a follow-up to abnormal changes detected with a Pap smear. The HPV test will continue to be researched and tested as it may be more accurate, alone or combined with Pap testing, when it comes to finding cervical cancer.
Accurate molecular diagnostic techniques that can be used to inform patient management and follow-up after treatment are now available for detection and identification of HPV. Exemplary molecular methods available for HPV detection and genotyping and their possible clinical utility are shown in Table 1 below.
TABLE 1HPV DNA test Method ComparisonDisadvantagesLaborious, timeMethodAdvantagesconsuming, a big amountIn situ hybridizationSpecificDNA needed.Hybrid Capture 2 High-RiskFDA approved,Low sensitivity comparedHPV DNA Testquantitative andwith PCR, not genotyping.detecting High-Risktypes.Type-specific PCRspecificLaboriousSequencingGood at identifyingUnsuitable clinically.new HPV types.qPCRHigh sensitivity, easyLow throughput, 1 to 2to operate and fast.targets in each reaction.